Shock absorbing device



Nov. 4, 1958 J. A-.- JoHNsoN SHOCK ABsoRBI'NG DEVICE Filed May 10, 1956'2 Sheets-Sheet 1 FIG. 3

' J. A. JOHNSON SHOCK ABSORBING DEVICE Nov. 4, 1958 Filed May 10, 1956 2Sheet-s- Sheet 2 FIG.9

,6 5 e, ,60 0 y Mw 4 300 7 14 w M w w M fw. mw, M *WT Af mw www m ma m4United States Patent O SHOCK ABsoRBING DEVICE John A. Johnson, ShortHills, N. J., assignor to ACF f Industries, Incorporated, New York, N.Y., a corporation of New Jersey Application May 10, 1956, Serial No.583,973

13 Claims. (Cl. 267-1) This invention relates to impact or shockabsorbing devices and particularly to a hydraulic rubber cushioningdevice for railway car draft gear. 'I'he invention also has otherapplications such as in railway car floating center sill structure andhold-down mechanism for highway trailers on railway cars, but isgenerally shown and described in connection with railway draft gear.

Standard friction iand rubber spring types of draft gear have certainadvantages and disadvantages. The friction type of gear employsspring-loaded friction elements and provides greater initial impactresistance, but tends to alternately bind and slide during operation andcloses positively or abruptly solid upon reaching its maximum energyabsorbing capacity. The rubber spring type gear utilizes rubber pads ormats interposed between and bonded to metal spacer plates and Whileinherently less resistant to initial impact than the friction type, doesnot `tend to go abruptly solid when closed and is satisfactory `forslightly higher impactvelocities. In addition, the standard types ofgear have an undesirable sharp recoil characteristic, the greater theimpact absorbing capacity `the shorter the draft gear travel. of draftgear travel would provide greater and more gradual energy absorption,but limitations are imposed Increasing the length by the size of thedraft gear pocket. Neither type of ystandard gear is satisfactory forpresent-day high impact velocities, where the energy in excess ofabsorption capacity of the gear must be absorbed by the car structure-and lading, frequently resulting in damage thereto.

'It is an Vobject of the present invention to provide a "shock absorbingcushioning device for railway car draft gear which eliminates thedisadvantages of the standard friction and rubber spring types of gearwhile retaining the advantages. i

Another object of the invention isto provide a device "as abovedescribed adapted to absorb the high velocity impacts of present-dayrailroad practice.

Still another object of the invention is to provide a"= hydrauliccushioning device of the character described in jgwhich 'a viscous fluidis pumped under pressure 'om chambers therein by compression on impactto increase `the energyabsorbing capacity of the draft gear.

" These and other objects of the invention will be ap-` 'Hparent to`those skilled in the art from a study of the Vfollowing descriptiontaken with the accompanying drawings,'in which:

' -Figure 1 isa perspective, partially broken-away view "showing thecushioning device of the present inventionV4 embodiedin a railway cardraft gear; Fig. 2 is a plan view of the draft gear assembly, certainparts being broken away to better disclose other parts;

Fig. `3 is a side elevational view of the draft gear assembly witha-flange of the center sill removed; v Fig. 4 is a sectional view takenon line 4 4 of Fig. 2;

, Fig. 6 yis a sectional view similar to Fig. 5, but show- -``ingtheunit `in solid orV compressed position;

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Fig. 7 is va sectional view taken on line 7 7 of Fig. 5 showing thegrooved end plate of the cushioning units;

Fig. 8 is a sectional view similar to Fig. 5 showing a modified form ofhydraulic -cushioning unit in normal position, and y Fig. 9 is asectional view similar to Fig. 8, but showing the modified form ofcushioning unit in solid `or compressed position.

Referring now more in detail to the drawings, the shock absorbing deviceis shown in Fig. 1 as applied to a railway car draft gear having acoupler 10 extending from center sill 12 with its shank 14 connected bykey 16 to a yoke 18. The key is arranged in slot 20 of the vyoke andprojects through slot 22 in the draft or center sill 12, as is standardpractice. The draft gear arrangement may be of any suitable type, suchas shown in Figs. 2 and 3, wherein the back face 24 of the yoke 18 isinterposed `between the forward and rear cushioning units 26, 28,respectively, of the shock absorbing device generally designated D. Thedevice is shown as installed in the standard draft gear pocket 30 ofcenter sill 12 between front and rear draft lugs 32, 34, respectively,and

due ltoits high energy absorbing capacity the units may be sufficientlysmaller than usual to permit inclusion of a standard rubber cushion unit36 in advance of the forward unit 26. The forces in buff are transmittedthrough the butt of coupler shank 14 and a front follower 15to eachofthe cushioning units 36, 26, 28, respectively, in series, while thedraft forces are absorbed through yoke back face 24 only by the forwardunit 26 of the device D and standard unit 36. However, this is merely byway of illustration, since either or both units 26, 28, of the devicemay be used with various other arrangements of transmitting forces to beabsorbed according to conditions and requirements.

One form of hydraulic cushioning unit or device` 26 is shown in Figs.4-7, and since itis essentially the same as unit 28, the `description ofit and reference numerals apply to both. The device comprises end plates38 between which are arranged a series of vertically disposedlongitudinally spaced pan-shaped metal plates 40 and an lorilice .diskor plate 42 adjacent one of the end plates. interposed or sandwichedbetween and bonded to these plates are perforated circular resilientmats or pads 44,

ofrubber or other elastic material, forming withthe plates a pluralityof contractable circumferentially spaced concentrically arrangedchambers 46 containing a suitable viscous hydraulic fluid. The rubberelements 44 may be in the form of concentrically arranged rings, formingtherebetween concentric annular -chambers 46.

The plates 40 between rubber elements 44 are provided withcircumferentially spaced passageways 48 extending .therethrough properlylocated to connect the chambers46 which are axially adjacent toeachother. The disk 42 adjacent end plate 38 is formed with orifices 50somewhat smaller than and located to communicate withl the passages 48.The orifices 50 in disk 42 are also in communication withcircumferential grooves 52 in end plate 38 which are in turn connectedby radially extending channels 54 leading to the periphery of the endplate exteriorly of the series of plates 40. The plates 40 are .arrangedin what may be termed partially nested relation pressed in resisting theimpact of either buff or draft forces, as shown in Fig. 6, the plates 40are moved closer together and the rubber elements 44 compressed ordistorted, contracting the size of chambers 46. The. contraction ofchambers 46 acts to pump hydraulic fluid therefrom under pressurethrough passages 48 in plates 40 and orifices 50 in disk 42 tocircumferential grooves 52 and radial channels 54 in the end plate 38.The fluid then finally enters the accumulator 58, which is slightlydistended or expanded in accommodating to the uid pressure, as alsoindicated in Fig. 6. It will be seen that in effect the sandwichesformed by the plates 40, rubber elements 44 and the pumping of fluidunder pressure from the intercommunicating contracting chambers 46arranged axially to each other act in series, while deformation of therubber elements 44 radially into chambers 46 act in parallel, to absorbthe energy of the impact. In other words, compression of the units 26 or28 contracts the -size of fluid containing chambers 46 both axially andradially, compression of plates 41B, rubber rings 44 and `contraction ofchambers 46 axially acting in series, while 'distortion of rings 44 andcontraction of chambers 46 radially acts in parallel. The frictionalengagement of adljacent diagonal rim portions 56 of plates 40 aidfurther in absorbing the shock as Well as acting to limit compression ofthe cushioning units. These rim or ange portions 56 also serve to limitdistortion or spreading of the outer edges of the outermost rubber rings44, thus further increasing contraction of the chambers 46 and theenergy absorbing capacity of the units. Upon decompression of the unitsto normal position as shown in Fig. 5, the elastic iluid accumulator 58contracts and the lluid is returned to chambers 46.

The cushioning unit per se of the modification shown in Figs. 8, 9 issimilar to that in Figs. 4-7 and the same reference numerals have beenapplied thereto, but a different type accumulator is used. In Figs. 8, 9the orifice plate 42 and the grooves and channels 52, 54 in the endplate 38 are omitted and instead one of the end plates is provided withprojecting outer and inner annular ribs 62, 64, respectively. The fluidaccumulator 66, of rubber or similar elastic material, is sealinglysecured to the ribs 62, 64 by any suitable means, such as outer andinner clamps or bands 68, 70, respectively. The elastic accumulator isenclosed by an annular housing 72 secured at its hub portion 74 to theIend plate 38 by a bolt 76. r[lhe end plate is provided withcircumferentially spaced orifices 78 extending therethrough and properlylocated to connect the passages 48 in plates 40 with the annular ordoughnut-shaped accumulator 66. Operation of the modiiied form of deviceis basically the same as described for Figs. 4-7, except that whencompressed, as shown in Fig. 9, the fluid is pumped directly through theorifices 78 in end plate 38 into an interior housed accumulator insteadof by way of an orifice disk to .a grooved and channeled end plate intoan exterior accumulator surrounding plates 40, as shown in Figs. 4-7.When decompressed to normal position, as shown in Fig. 8, theaccumulator deates and fluid returns to chambers 46, the same as`described for Figs. 4-7.

From the foregoing description it is believed clear that a shocklabsorbing device has been provided having the necessary increasedenergy absorbing capacity to withstand present-day high velocityimpacts. The pum-ping of hydraulic fluid under pressure, together withthe advantages of the rubber cushioning elements, increases especiallythe initial impact absorbing capacity of the device while reducing to aminimum the tendency in standard devices to close positively solid. Inaddition, the recoil of the present device is more gradual or lessabrupt than in the standard friction type device.

The invention may be modified in various respects as l will occur tothose skilled in the art, and the exclusive use of all suchmodifications that come Within the scope of the appended claims iscontemplated.

What is claimed is:

l. In `a hydraulic shock absorbing cushioning device, end plates, aseries of vertically arranged longitudinally spaced metal plates betweensaid end plates, resilient mats interposed between and bonded to saidspaced plates, a plurality of contractable hydraulic iluid containingchambers within said device, an expansible ac-cumulator associated withsaid device, and passageways connecting said chambers to permit pumpingof fluid under pressure therefrom during compression of said device, atleast one of sai-d end plates being formed with means connecting saidpassageways with said accumulator for passage of fluid pumped from saidchambers into said accumulator.

2. In a hydraulic shock absorbing cushioning device, end plates, aseries of vertically arranged longitudinally spaced circular metalplates between said end plates, resilient mats inter-posed between andbonded to said spaced plates, said mats being formed to provide aplurality of axially spaced contractable hydraulic iiuid 4containingchambers within said device, an `expansible accumulator associated withsaid device, and passageways extending through said spaced platesconnecting said axially spaced chambers to permit pumping of iluid underpressure therefrom during compression of said device, at least one ofsaid end plates being provided with means connecting said passagewayswith said accumulator whereby fluid pumped from said chambers isreceived in said accumulator.

3. In a hydraulic shock absorbing cushioning device, end plates, aseries of vertically arranged longitudinally spaced circular metalplates between said end plates, resilient mats interposed between andbonded to said spaced plates, said mats being formed to provide aplurality of contractable hydraulic fluid containing chambers withinsaid 'device radially and axially spaced from each other, `an expansibleaccumulator associated with said device, and passageways extendingthrough said spaced plates connecting the axially spaced chambers topermit pumping of iluid under pressure therefrom during compression ofsaid device, at least one of said end plates being formed with meansconnecting said passageways with said accumulator for passage of uidpumped from said chambers into said accumulator.

4. In a hydraulic shock absorbing cushioning device, end plates a seriesof vertically yarranged longitudinally spaced` circular metal platesbetween said end plates, resilient concentric rings interposed betweenand bonded to said spaced plates, said concentric rings forming withsaid plates a plurality of contractable hydraulic lluid containingchambers therebetween, an expansible accumulator associated with saiddevice, yand passageways extending through said spaced plates connectingsaid chambers to permit pumping of liuid under pressure therefrom duringcompression of said device, at least one of said end plates being formedwith means connecting said passageways with said accumulator for passageof uid pumped from said chambers into said accumulator.

5. In a hydraulic shock absorbing cushioning device, end plates, aseries of vertically arranged longitudinally spaced pan-shaped metalplates between said end plates, resilient mats sandwiched between andbonded to said spaced plates, said mats being formed to provide aplurality of contractable hydraulic uid containing chambers within saiddevice, an expansible accumulator associated with said device, andpassageways extending through said spaced plates connecting saidchambers to permit pumping of iiuid under pressure therefIom duringcompression of said device, said pan-shaped plates being forced towardnested position whereby the rim portions thereof interengage to limitcompression of said device, at least one of said end plates being formedwith means connecting said passageways with said accumulator for passageof fluid pumped from said chambers into said accumulator.v

6. In a hydraulic shock absorbing cushioning device, end plates, aseries ofvertically arranged longitudinally spaced pan-shaped metalplates between said end plates, resilient concentric rings sandwichedbetween and bonded to said spaced plates, said concentric rings formingwith said plates a plurality of contractable hydraulic uid containingchambers therebetween, passageways extending through said spaced platesconnecting said chambers to permit pumping of uid under pressuretherefrom during compression of said device, said pan-shaped platesbeing forced toward nested position whereby the rim portions thereofinterengage to limit spreading of the outer edges of the outermostconcentric rings, and an expansible accumulator associated with saiddevice, one of said end plates being formed with means connecting saidpassageways with said accumulator whereby uid pumped from said chambersis received in said accumulator.

7. In a hydraulic shock absorbing cushioning device, end plates, aseries of vertically arranged longitudinally spaced plates between saidend plates, resilient mats interposed between and bonded to said spacedplates, said mats being formed to provide a plurality of contractablehydraulic fluid containing chambers within said device, an expansibleaccumulator surrounding said series of spaced plates and sealinglysecured to said end plates, and passageways extending through saidspaced plates connecting said chambers topermit pumping of uid underpressure therefrom during compression of said device, at least one ofsaid end plates being provided with means connecting said passagewayswith said accumulator whereby fluid pumped from said chambers isreceived in said accumulator.

8. In a hydraulic shock absorbing cushioning device, end plates, aseries of vertically arranged longitudinally spaced plates between saidend plates, resilient mats sandwiched between and bonded to said spacedplates, said mats being formed to provide a plurality of contractablefluid containing chambers within said device, passageways extendingthrough said spaced plates connecting said chambers to permit pumping offluid under pressure therefrom during compression of said device, and anexpansible accumulator surrounding said series of spaced p lates andsealingly secured to said end plates, one of said end plates havingchannels'therein connecting said passageways with said accumulatorwhereby uid pumped from said chambers is received in said accumulator.

9. In a lhydraulic shock absorbing cushioning device, end plates, aseries of vertically arranged longitudinally spaced plates between saidend plates, resilient mats interposed between and bonded to said spacedplates, said mats being formed to provide a plurality of contractableuid containing chambers within said device, passageways extendingthrough said spaced plates connecting said chambers to permit pumping offluid under pressure therefrom during compression of said device, ahousing secured to one of said end plates, and an expansible accumulatorwithin said housing sealingly secured to said end plate, said end platehaving orifices therethrough connecting said passageways with saidaccumulator whereby fluid pumped from said chambers is received in saidaccumulator.

l0. In a lhydraulic shock absorbing cushioning device, end plates, aseries of vertically arranged longitudinally spaced plates between saidend plates, resilient concentric rings interposed between and bonded tosaid spaced plates, said concentric rings forming with said plates aplurality of contractable hydraulic uid containing chamberstherebetween, an expansible accumulator surrounding said series ofspaced plates and sealingly secured to said end plates, and passagewaysextending through said spaced plates connecting said chambers, saidspaced plates and resilient rings acting in series and the latter alsoin parallel to pump lluid from said chambers during compression of saiddevice, one of said end plates being formed with means connecting saidpassageways with said accumulator whereby fluid pumped from saidchambers is received in said accumulator.

1l. A hydraulic shock absorbing cushioning device comprising, endplates, a series of vertically arranged longitudinally spaced circularmetal plates between said end plates, concentric rings of rubbersandwiched between and bonded to said spaced plates, said rubber ringsforming with said spaced plates a plurality of concentric chamberstherebetween contractable in size when said device is compressed byimposition of impact thereon, a viscous uid in said chambers,circumferentially spaced passageways extending through said spacedplates connecting said chambers, said spaced plates and rubber ringsacting in series and said rubber rings also in parallel upon compressionof said device to pump uid from said chambers, and an elasticaccumulator casing enclosing said series of plates and sealingly securedto said end plates, at least one of said end plates being provided withcircumferential and radial channels connecting said passageways andaccumulator for passage of uid pumped from said chambers into saidaccumulator.

l2. A hydraulic shock absorbing cushioning device including end platesand a series of vertically arranged longitudinally spaced circular metalplates having diagonal peripheral flanges between said end plates,rubber pads sandwiched between and bonded to said spaced plates, saidrubber pads being formed to provide a plurality of contractablehydraulic fluid containing chambers within said device, passagewaysextending through said spaced plates connecting said chambers wherebyuid is pumped therefrom under pressure during compression of said deviceto absorb the energy of impact imposed thereon, said plate flanges beingforced int-o frictional engagement to increase said energy absorption,and an elastic accumulator surrounding said series of spaced plates andsealingly secured to said end plates, one of said end plates beingformed with means connecting said passageways with said accumulatorwhereby uid pumped from said chambers is received in said accumulator.

13. A hydraulic shock absorbing cushioning device including end platesand a series of vertically arranged longitudinally spaced circular metalplates between said end plates, circular rubber mats sandwiched betweenand bonded to said spaced plates, said rubber mats being perforated toform with said plates a plurality of contractable circumferentiallyspaced concentrically arranged hydraulic iluid containing chamber withinsaid device, passageways extending through said spaced plates connectingsaid chambers whereby fluid is pumped therefrom under pressure duringcompression of said device to absorb the energy of impact imposedthereon, and an expansible accumulator associated with said device, oneof said end plates being formed with means connecting said passagewayswith said accumulator whereby fluid pumped from said chambers isreceived in said accumulator.

References Cited in the le of this patent UNITED STATES PATENTS2,187,156 Johnson Jan. 16, 1940 2,445,723 Brown July 20, 1948 2,504,424Kraak Apr. 18, 1950 2,537,634 Brown Jan. 9, 1951 FOREIGN PATENTS 734,947Great Britain Aug. 10, 1955

